Structural diversity and phylogenetic distribution of C-terminal regions of archaeal Top6B orthologs. The phylogenetic tree of archaeal Top6B orthologs (Fig. 7) is shown with the rooting chosen arbitrarily. DNA gyrase-encoding clades are colored in red, clades lacking DNA gyrase are in black and mixed clades (with both gyrase-encoding and gyrase-less organisms) are colored in purple. AlphaFold2-predicted model structures of Top6B C-terminal extremities from representative organisms of each clade are shown. The structures are colored by the pLDDT confidence index (see also supplementary fig. 12, Supplementary Material online).